The amateur scientist.

X amateur who builds a radio trans­ mitter is likely to measure his success and pleasure in terms of the transmission range he achieves. In such terms there is more pleasure in talking with another "ham" across the country than with one in the next coun­ ty, even if the more distant operator turns out to be a rather dull fellow. The aim of reaching out ever farther has spurred amateur radio operators to extend the range of their apparatus steadily; it was about five miles in 1900, rose to 5,000 miles by 1920 and reached 12,000 miles in 1930. The ultimate in distance was approached recently when an amateur in Finland communicated with one in California by means of sig­ nals bounced off the moon. The round trip was some 500,000 miles. What next? R. Stuart Mackay, a physicist and biologist at Boston Univer­ sity, suggests that radio experimenters shift their enthusiasm to short-range te­ lemetry. H�re apparatus the size of a vi­ tamin capsule radiates signals over dis­ tances measured in feet or even inches. The challenge lies in making the most of the least.